Showing papers in "Taxon in 1990"
TL;DR: This second edition has been completely revised and has incorporated significant changes that have occurred in wood anatomy over the past years.
630 citations
TL;DR: The Chromophyta, past and present, and the Kingdom Chromista - problems and perspectives: a summarizing view.
Abstract: T. Christensen: The Chromophyta, past and present S.W. Jeffrey: Chlorophyll c pigments and their distribution in the chromophyte algae T. Bjornland and S. Liaaen-Jensen: Distribution patterns of carotenoids in relation to chromophyte phylogeny and systematics J.A. Raven, A.M. Johnston, and M. bin Surif: The photosynthetic apparatus as a phyletic character R.A. Cattolico: Analysis of chloroplast evolution and phylogeny K.V. Kowallik: Molecular aspects and phylogenetic implications of plastid genomes of certain chromophytes J.M. Whatley: Chromophyte chloroplasts - a polyphylectic origin? B.S.C. Leadbeater: The phylogenetic significance of flagellar hairs in the Chromophyta H.R. Preisig: The flagellar base ultrastructure and phylogency of chromophytes J.C. Green: Relationships between the chromophyte algae: the evidence from studies of mitosis J.D. Dodge: Phylogenetic relationships of dinoflagellates and their plastids M.N. Clayton: Brown algae and chromophyte phylogeny C.J. O'Kelly: The evolutionary origin of the brown algae: information from studies of motile cell structure P. Heywood: Some affinities of the Raphidophyceae with other chromophyte algae R.M. Crawford and F.E. Round: Corethron and Mallomonas - some striking morphological similarities C.G. Mann and H.J. Marchant: The origins of the diatom and its life cycle G.W. Beakes: Oomycete fungi: their phylogeny and relationship to chromophyte algae D.J.S. Barr and N.L. Desaulniers: The flagellar apparatus of the Oomycetes and Hyphochytriomycetes D.J. Patterson: Stramenopiles: chromophytes from a protistan perspective T. Cavalier-Smith: The Kingdom Chromista F.E. Round: The chromophyte algae - problems and perspectives. A summarizing view. Index.
216 citations
TL;DR: The lichen genus Xanthoparmelia is characterized by the presence of usnic acid in the cortex, a positive lichenin test, oil bodies in the rhizines, saxicolous or terricolous habit, uniform small ellipsoid colorless spores, and bifusiform or rarely cylindrical conidia.
Abstract: Hale, Mason E. A Synopsis of the Lichen Genus Xanthoparmelia (Vainio) Hale (Ascomycotina: Parmeliaceae). Smithsonian Contributions to Botany, number 74, 250 pages, 75 figures, 1990.—A world-level synopsis is presented for Xanthoparmelia with full synonymies, typLFication of all taxa, species descriptions, and keys. The genus is characterized by the presence of usnic acid in the cortex, a positive lichenin test, oil bodies in the rhizines, saxicolous or terricolous habit, uniform small ellipsoid colorless spores, and bifusiform or rarely cylindrical conidia. The lower surface is rhizinate except in a few species and brown or black. Cilia are lacking. The 406 species occur primarily in southern Africa (212) and Australia (145). Two new species are described; X. greytonensis Hale and X. kasachstania Hale. Four new combinations are made: X. mutabilis (Taylor) Hale, X. perplexa (Stizenberger) Hale, X. sigillata (Brusse) Hale, and X. verecunda (Bmsse) Hale. One new name is proposed: X. neopropaguloides Hale. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution’s annual report, Smithsonian Year. Series cover DESIGN; Leaf clearing from the katsura tree Cercidiphyllum japonicum Siebold and Zuccarini. Library of Congress Cataloging in Publication Data Hale, Mason E. A synopsis of the lichen genus Xanthoparmelia (Vainio) Hale (Ascomycotina, Parmeliaceae) / Mason E. Hale (Smithsonian contributions to botany ; no. 74) Includes bibliographical references. SupL of Docs, no.: SI 1.29:74 1. Xanthoparmelia—Classification. I. Title. II. Series. QKLS2747 no. 74 [QK585.P2] 581s-dc20 [589.1] 89-600293
135 citations
TL;DR: The EcSC provides a useful conceptual framework for experimentation and observation at the interface between taxonomy and ecology and has the potential to explain on a universal basis variation in diversity and reproductive patterns.
Abstract: Summary In both folk taxonomy and science, the idea of species is based on the observation that phenotypic variation is discrete and not continuous. The definition of the species category, the "what," must therefore be restricted to these empirically demonstrable facts. To avoid circularity, concepts about the biological nature of species, the "whys," must be kept separate from the criteria by which individual species are circumscribed. Such ideas are models and can only be judged in terms of their capacity to bring observations into a meaningful context. The Biological Species Concept (BSC), the Evolutionary Species Concept (EvSC) and the Ecological Species Concept (EcSC) are models, not definitions. The BSC has its principal flaw in its inability to deal with uniparentally reproducing organisms. It fails to identify the driving force of speciation. It therefore fails to predict diversity and to explain why different species have different reproductive strategies. The EvSC fails to explain why different lineages are phenetically different. It fails, therefore, to explain why species arise, and why there are differences in diversity and reproductive strategies. The EcSC has the potential to make a direct connection between environment and phenetic variation patterns. It provides a useful conceptual framework for experimentation and observation at the interface between taxonomy and ecology and has the potential to explain on a universal basis variation in diversity and reproductive patterns. In some taxonomically difficult cases it also sheds light on the nature of variation patterns and might therefore help in taxonomic judgment where the BSC is conceptually inapplicable and the EvSC fails to provide useful concepts.
111 citations
66 citations
65 citations
TL;DR: A key to putatively monophyletic groups in American Stipeae and a synopsis of Nassella s.l., involving more than 60 new combinations of Stipa L. described by Spegazzini are presented.
Abstract: The taxonomic history of Nassella Desv is reviewed and its circumscription expanded to include all species of Stipeae with strongly overlapping lemma margins; lemma apices that are fused into a crown; paleas that are highly reduced, ecostate, and glabrous; long epiblasts; and lemma epidermes with very short fundamental cells having silicified cell walls The expanded genus includes 79 species, almost all of which are South American Piptochaetium and Stipa sect Hesperostipa are suggested as the closest extant relatives Synapomorphies of the three taxa are: brownish callus hairs; fused lemma apices; bulbous-based lemma cilia; silicified lemma fundamental cells; and long epiblasts A key to putatively monophyletic groups in American Stipeae and a synopsis of Nassella sl, involving more than 60 new combinations, are presented The transferred species include representatives from seven subgenera of Stipa L described by Spegazzini
47 citations
TL;DR: In preparation for continued phenetic and cladistic studies of taxonomic relationships of Centrospermae, 16 families are recognized in the order, and putative autapomorphies are designated for each where known, in order to support their monophyletic status.
Abstract: Summary In preparation for continued phenetic and cladistic studies of taxonomic relationships of Centrospermae, 16 families are recognized in the order, and putative autapomorphies are designated for each where known, in order to support their monophyletic status. Polyphyly in Phytolaccaceae s.l. and paraphyly in Caryophyllaceae, Chenopodiaceae, and Portulacaceae are discussed. Pollen and floral characters used in an early study are revised and recoded. Recent molecular data bearing on centrosperm phylogeny are summarized.
TL;DR: Working with Australian native and introduced species of Eragrostis, Prendergast et al. (1986) showed that these anatomical types are not indicative of the different types of C4 photosynthetic decarboxylation, as previously thought.
Abstract: Mircohairs of grasses are characteristic bicellular trichomes, commonly found on the leaves but also occurring elsewhere on the plant (e.g., lemmas, paleas and lodicules: Tateoka et al., 1959; Metcalfe, 1960; Tateoka and Takagi, 1967; Takeoka, 1976; Scholz, 1979; Terrel and Wergin, 1981). They are lacking in the subfamily Pooideae but almost universally present in the other subfamilies (Johnston and Watson, 1976; Watson et al., 1985; Amarasinghe and Watson, 1988), and their presence or absence is widely used as a taxonomic character (Prat, 1936; Metcalfe, 1960; Watson et al., 1985; Watson et al., 1986; Watson and Dallwitz, 1988). Morphologically, microhairs are generally classified into three major types (Tateoka et al., 1959; Metcalfe, 1960; Johnston and Watson, 1976), viz., the 'chloridoid type', with relatively short, broad (approaching hemispherical) and thick walled cap cells; the 'panicoid type', with relatively long, narrow and thin walled, elongated cap cells; and the 'Enneapogon type', with very long (up to 400 mm) basal cells and ovoid cap cells. These morphological types also have taxonomic significance. With only a few exceptions, the 'chloridoid type' is confined to the subfamily Chloridoideae; the 'panicoid type' occurs throughout the subfamilies Panicoideae, Arundinoideae and Bambusoideae, and in a few genera of Chloridoideae; and the 'Enneapogon type' is known only from four genera of the tribe Pappophoreae (subfamily Chloridoideae), from Neeragrostis Bush, and from the genus Amphipogon R. Br. (Arundinoideae-Danthonieae: Tateoka et al., 1959; Watson et al., 1985; Watson et al., 1986; Amarasinghe and Watson, 1988). There is sometimes marked variation in the morphology of microhairs from different parts of the same plant (e.g., leaves versus spikelet parts of Amphipogon strictus R. Br.); but most genera seem to be constant for those on the abaxial surface of the leaf blade, which most of the available data represent. Eragrostis is a striking exception, with 'chloridoid type', 'panicoid type' and even intermediate forms in different species (Tateoka et al., 1959). Eragrostis is also heterogenous in its photosynthetic carbon reduction (PCR) or 'Kranz' bundle sheath anatomy, as determined by the position and shape of the PCR chloroplasts and the type of PCR sheath outline (Ellis, 1977; Prendergast et al., 1986). Working with Australian native and introduced species of Eragrostis, Prendergast et al. (1986) showed that these anatomical types are not indicative of the different types of C4 photosynthetic decarboxylation, as previously thought (Gutierrez et al., 1974; Hatch et al., 1975; Brown, 1977), all those studied biochemically being of type NAD-ME. On the other hand, the three PCR sheath anatomical types of Eragrostis, referred to by Prendergast et al. (1986) as 'PCK-like' (centrifugally positioned, ovoid chloroplasts and an uneven sheath outline), 'NAD-ME-like' (centripetally positioned, elongated chloroplasts and an even sheath
TL;DR: Hagstr6m's concepts of relationships in Potamogeton, as reflected by the subgeneric, sectional, and subsectional divisions in his classification of the genus are investigated by reconstruction of an evolutionary "tree" deduced from phylogenetic inferences stated in his monograph.
Abstract: Summary Hagstr6m's concepts of relationships in Potamogeton, as reflected by the subgeneric, sectional, and subsectional divisions in his classification of the genus are investigated by reconstruction of an evolutionary "tree" deduced from phylogenetic inferences stated in his monograph. These relationships are explored in the context of results from phenetic and cladistic numerical analyses performed using characters taken from the Hagstr6m monograph that are scored for 26 subsections. The Hagstrom classification represents an amalgam of phenetic and cladistic interpretations and the hierarchy does not depict accurately fundamental evolutionary relationships indicated by numerical analyses. Recommendations are provided for developing and testing evolutionary hypotheses that are independent of relationships inferred by this long-standing but problematic classification.
TL;DR: A list of all known generic names in Annonaceae, including orthographic variants and nomina nuda, is offered and topics include place and date of original publication, synonymy, and typification.
Abstract: Introduction In 1983, a multidisciplinary investigation program on the systematics of Annonaceae was started at Utrecht. The two main goals are to provide an up-to-date classification of the family, and the publication of a series of monographs for Flora Neotropica (Maas, 1983). The Annonaceae are a pantropical family with ca. 2000 species in ca. 130 genera. Study of the vast literature on this family in the meantime has resulted in "Index to neotropical taxa of Annonaceae" (Maas et al., 1987), "Bibliography of the Annonaceae" (Mennega, 1985; second edition, 1989), and "Iconography of the Annonaceae" (Mennega, in prep.). The present paper offers a list of all known generic names in Annonaceae, including orthographic variants and nomina nuda. Topics include place and date of original publication, synonymy, and typification. Data were extracted from various publications of R. E. Fries (1900-1959), papers on Annonaceae by other authors, and from Farr et al.: Index Nominum Genericorum (1979, 1986).
TL;DR: Heterochrony results in the condition of paedomorphosis, the retention of juvenile features of an ancestor in adults of a descendent, which is recognized in the animal kingdom and among flowering plants.
Abstract: Summary Recently, attention has been focused on the evolutionary role of heterochrony (phyletic change in the timing of development). Heterochrony results in the condition of paedomorphosis, the retention of juvenile features of an ancestor in adults of a descendent. Relatively few examples of evolution via heterochrony are known among flowering plants, due to the vague demarcation of juvenile and adult stages. Recent systematic studies among the endemic Hawaiian Lobelioideae (Campanulaceae) have revealed the occurrence of a significant example. The endemic genus Cyanea includes several species that produce morphologically distinct juvenile forms. The four species of the C. solanacea complex form a monophyletic lineage in which the adults of each species resemble juveniles of the next more primitive species, i.e., adults of the more derived species are progressively more juvenile in appearance. It is hypothesized that the C. solanacea complex is a paedomorphic lineage, in which successive heterochronic events have produced a sequence of progressively more paedomorphic species. The publication of Ontogeny and Phylogeny (Gould, 1977) renewed interest in the role of heterochrony in evolution. Gould defined heterochrony as phyletic change in the timing of development, i.e., as an acceleration or retardation of the rate of development in a descendent as compared to that of an ancestor. As such, evolution proceeds not necessarily through major changes in the genome, but rather by changes in the timing of gene action. Acceleration of development in reproductive structures is termed progenesis, while retar- dation of development in somatic organs is termed neoteny. Either of these heterochronic processes results in the condition of paedomorphosis, the retention of juvenile features of an ancestor in adults of a descendent. Thus, paedomorphic species are often described as permanently juvenile. Changes in the timing of development might simply form part of a species' normal phenotypic variation. However, if the resulting changes in morphology are favored by selection, these paedomorphic individuals might become established and re- productively isolated, with speciation as the eventual result (McNamara, 1982). Although paedomorphosis long has been recognized in the animal kingdom, heterochrony rarely has been invoked as a major evolutionary process among plants (Takhtajan, 1972). Carlquist (1962a) demonstrated the paedomorphic nature of secondary xylem. More recent studies have suggested that heterochrony has been operative in the evolution of cleistog- amous flowers (Lord and Hill, 1987), ornithophilous flowers (Guerrant, 1982), and mosses (Mishler, 1986). Perhaps one reason that clear botanical examples of paedomorphosis have been lacking is that plants seldom produce distinct juvenile and adult stages. The concept of adulthood has two aspects: onset of sexual reproduction and cessation of somatic growth (Guerrant, 1982). In plants, due to their perpetually embryonic meristems, these two aspects are not as tightly linked as in animals. Typically, onset of reproduction is associated instead with the attainment of some minimum size, and somatic growth continues long afterward. The ephemeral nature of plant reproductive structures, as compared to those of animals, also vitiates the strict demarcation of juvenile and adult in plants. For these reasons, certain species of the endemic Hawaiian genus Cyanea Gaudich. (Campanulaceae: Lobelioideae) are of interest for the production of morphologically distinct juveniles.
TL;DR: The present paper may be considered as an introductory paper to forthcoming publications of general studies on flower and fruit characters now being conducted at Utrecht.
Abstract: A comparative survey of several historical classifications of Annonaceae down to the subtribal level is given. The role of various key characters is briefly discussed. The present paper at the same time may be considered as an introductory paper to forthcoming publications of general studies on flower and fruit characters now being conducted at Utrecht.
TL;DR: Hieracium subgenus Chionoracium Schultz-Bip is a distinct group of New World hawkweeds, different enough from other hieracia to cause Sell (1987) to suggest that the group belongs in Crepis.
Abstract: Hieracium subgenus Chionoracium Schultz-Bip. is a distinct group of New World hawkweeds, different enough from other hieracia to cause Sell (1987) to suggest that the group belongs in Crepis. In the last revision of the entire subgenus, Zahn (1922) recognized 122 species (according to my circumscription of the group). Torrey and Gray (1843) first grouped together the native North American hawkweeds having involucral bracts arranged in a short outer series and a much longer inner series. Fries (1848) made this group, Stenotheca, one of his primary divisions of Hieracium, and included in it nearly all the species native to North and South America, along with a few species of Europe, Africa, and India. In 1862, Fries recognized Stenotheca as a subgenus, and Peter (1894) and Zahn (1922) followed this treatment. Schultz (1861), however, had already published his subgenus Chionoracium for six species of American hawkweeds with a white pappus. This name must therefore supersede Stenotheca.